Hawaiian Volcanoes:
Fire Walking With the Lava Junkies
From Fun on the Net with additions
by Joe Naumann, UMSL
The “Big Island”
• The only active volcanoes in Hawaii today are
found on the Big Island of Hawaii. These are
dome, or shield, volcanoes that have formed
over a hotspot on the Pacific plate. The older,
smaller islands had active volcanoes when
they were located over the hotspot. They are
smaller now than they were before because
today erosion from waves has reduced them
in size.
HAWAII
• The Hawaiian Islands are at the southeastern
end of a chain of volcanoes that began to
form more than 70 million years ago. Many
of these volcanoes formed islands that have
subsided and eroded beneath sea level, and
some of the old volcanoes probably never
reached sea level. Each Hawaiian island is
made of one or more volcanoes, which first
erupted on the sea floor and only emerged
above the ocean's surface after countless
eruptions.
• The largest and most southeastern
island of the chain, Hawai`i, consists of
five volcanoes. Kilauea, Mauna Loa, and
Hualalai have erupted in the past 200
years. Lo`ihi, the youngest volcano of
the Hawaiian Volcanic Chain, is still
about 1,000 meters beneath the ocean's
surface. East Maui Volcano, commonly
known as Haleakala, on the island of
Maui, is the only other Hawaiian
volcano to have erupted since the late
1700's.
• Map of the southeastern or "windward" Hawaiian
Islands. The islands owe their existence to a "hot
spot" in the Earth's mantle that has changed
location only slightly over the past 70 million years.
This hot spot is located beneath the southeastern
part of Hawai`i.
Oldest island
Youngest island
• Map of the Hawaiian Islands on the previous
slide, shows a chain of volcanoes that stretches
about 2,700 km in a northwesterly direction
from the Island of Hawai`i. The age of the
volcanoes that form the islands increases
progressively from Hawai`i, where the volcanoes
are still active, to the northwest end, where the
volcanoes are about 30 million years old. The
chain of volcanoes continues as seamounts for
another 3,000 km; the chain bends sharply to
the northward about 700 km beyond this map
and becomes the Emperor Seamounts.
Map of Kilauea Eruptions 1983 present
The Adventure
• "We took a helicopter to the rim and hiked
about a mile [1.6 kilometers] into the
steaming cauldron of Kilauea's Pu'u 'O'o
crater to this skylight. Geologists call the
skylight the Cookie Monster because it really
looks like the shape of the character on
Sesame Street.“From the helicopter, we saw
lava splashing and frothing 50 feet [15
meters] below the surface in these 75- to
100-foot-wide [23- to 30-meter-wide] pools.
Plumes of gas escaping from vents as
lava meets air
Lava breaks out of its shell of
hardened, black rock
• This is a breakout, or a live surface flow of
molten rock. The magma was oozing under
the skin of cooled black rock—it's hotter than
hell up there. Eventually a buildup of
pressure under a certain place will crack the
surface over it, and the lava will break out.
The Highcastle lava bench (new land
that is formed as lava cools)
• This was our final quest—the ocean entry at
Highcastle, the holy grail for lava photographers.
The lava was coming over the last cliff before
entering the ocean.
A lava breakout from newly cooled
rock
• This is wild. As the drops break out down the
slope, the pressure moving the lava, pushing
on the cooling skin above it, twists the skin
into ropes. This is classic pahoehoe lava. Even
where I was standing, the temperature
underfoot was a few hundred degrees
[approximately 150°C] at least, and there are
radiant rocks above me.
Lava spiraling down a slope
• This shot may look like a dreamy day on the
side of a volcano, but it was really wicked. I
am standing downwind of an a'a flow, which
is notorious for emitting an exceptional
amount of radiant heat. It was really, truly
ferociously hot.
The deceptive calm of an extremely
hot flow